Spark plug-flash ignition type



Feb. 6, 1934. w, 1 STEPHENSON 1,945,870

SPARK PLUG-FLASH IGNITION TYPE Filed June 11, 1931 Patented Feb. 6, 1934 UNITE STES islaam SARK PLUG- FLASH IGNE'IION TYPE William l. Stephenson, Bingham Lake, Minn.

l Claim.

rlhis invention relates to improvements in spark plugs for internal combustion engines and has for a general object the provision of a simple, improved and comparatively inexpensive spark 5 plug of the flash ignition type securing more efiicient operation in the ignition of the combustive gases, having greater durability and preventing the formation of a carbon deposit upon the electrodes and insulator. 1 It is a further object to provide a flash ignition spark plug which will instantaneously ignite the fuel gas within the combustion chamber of an engine by means of flames distributed radially and preferably also downwardly from apertures in the wall of the plug producing an exceedingly rapid propagation of combustion.

It is a further object to provide in a spark plug of the type above described a small explosion chamber surrounding the electrodes and insulator of the spark plug and shielding the insulator from the intense heat generated by the oombustion or the explosive mixture in the combustion chamber of the engine and also preventing the formation oi a carbon deposit on the elec- 5 trodes and insulator.

My spark plug is so constructed that considerable distribution of flame into the combustion chamber is effected giving the engine a quicker and more powerful explosion and the said small 30 explosion chamber which surrounds the electrodes and insulator is so constructed and vented that dead gases cannot remain therewithin.

The electrodes are so disposed within the auxiliary explosion chamber that the spark gap will be positioned axially thereoiand centrally with reference to the several vents in the peripheral wall. Another important feature of my invention is that the entire auxiliary explosion chamber formed about the electrodes and insulator is o disposed within the combustion or firing chamber of the engine thereby permitting a greater flame distribution for propagation of combustion and enabling the interior of the explosion chamber to be quickly and thoroughly vented upon the suction stroke of the engine.

These and other objects and advantages of the invention will be more fully set forth in the following description made in connection with the accompanying drawing, in which like reference characters refer to similar parts throughout the several views, and in which:-

Fig. 1 is a sectional view or" the top of a cylinder of an internal combustion engine showing the embodiment of my improved spark plug operatively applied thereto;

low the lower end of insulator bushing 5 form- Serial No. 543,596

Fig. 2 is a cross section-taken on the line 2-2 or" Fig. l showing the arrangement of the electrodes with respect to the peripheral wall of the explosion chamber and also showing the ports through the bottoni of said chamber;

Fig. 3 is a fragmentary View partly in side el e vation and partly in vertical section showing a somewhat different form of my invention and Fig. i is a cross section taken on the line 4-74 of Fig. 3. j y

In the embodiment of my invention illustrated in Figs. l and 2 my plug is tapped in conventional manner into the upper end of the combustion chamber of an internal combustion engine, portions of the water jacket of the engine being indicated by the letter W. v

The upper portion of my plug is of the con ventional type including an insulator bushing VV5 in which is longitudinally mounted the usual metallic rod 6 projecting from the upper end thereof to form an electrical terminal which may be fitted with a threaded nut 7 for clamping the attachment piece 8 of a conductor thereto. The lower end or rod 6 projects for some distance be- S0 ing an electrode which, as shown,. is disposed axially of the plug. Insulator 5 is surrounded at its medial portion by means of a metallic shell or plug 9 and said shell has a cylindrical and reduced lower portion or hollow extension '901. forming al spark plug explosion chamber E which is disposed concentrically of electrode 6 andlsui rounds both electrodes and the lower end of insulator bushing 5. The usualv threaded gland l0 surrounds the upper portion of insulator bushing 5 and is threadedly engaged with the upper and enlarged portion of shell 9.

It will be noticed that the lower portion 5a of said insulator is enlarged to snugly iit the peripheral wall of the intermediate portion of shell or plug 9 and if desired non-combustible packing material, such as a strip of asbestos maybe disposed between the enlargement 5a and theperipheral wall of the plug to formT anair-tight joint between the two. Insulator bushing 5 terminates in the usual diminished extremity 5bv disposed axially of the plug.

The hollow extension 9a which forms explosion chamber E is disposed entirely within the combustion chamber of the engine and it will be .105 noted that the enlargement 5a, of the insulator bushing is disposed substantially on a line with the top of the combustion chamber. The second electrode ll ci the plug is carried by the peripheral wall of the hollow extension 9a and'spaced i110 below the electrode 6 to form a spark gap located centrally and axially of the explosion chamber E.

The hollow extension of the shell 9a has a closed bottom provided, as shown in Figs. 1 and 2, with one or more flame discharge apertures 9b which may be of any suitable shape or size and are preferably symmetrically arranged with reference to the axis of the extension. The peripheral wall of the hollow extension is also provided with a series of spaced flame discharge apertures 9b and it will be noted that some of said apertures are disposed at the topmost portion of the explosion chamber E while others are disposed circumferentially at the lower portion of the chamber, the above recited arrangement as will hereafter more fully appear effecting a thorough and rapid venting of the entire spark plug explosion chamber upon the suction stroke of the engine.

In the operation of my spark plug it Will be seen that the suction of the cylinder of an engine creates a vacuum in the spark plug explosion chamber E which being completely disposed within the combustion chamber of the cylinder, quickly is vented and completely filled with an explosive fuel mixture. Upon the compression stroke of the engine the compressed gas within explosion chamber E is ignited by the spark produced by the electrodes 6 andV 11 and it will-be noticed that this spark is disposed substantially axially and centrally of chamber E. The explosion of combustive gases in chamber E causes names to be shot out radially through the several side ports 9b in the peripheral wall of the shell extension 9a. Other flames are shot out through the ports 9b in the bottom of the explosion chamber. The several ames emanate from the center of the spark plug explosion chamber and practically instantaneously ignite the explosive mixture within the combustion chamber of the engine effecting a wide distribution of iiame and a very rapid and complete propagation of combustion.

The electrodes 6 and 11 as well as the depending and enlarged end of the insulator bushing 5a and insulator extremity 5b are housed and shielded by the closed shell extension 9a and are consequently not subjected to the intense heat of the explosion since the shell and its extension carries outby conduction a substantial portion of the heat. Burned gas cannot accumulate in the explosion chamber E since it will be noticed that the entire chamber is disposed within Vthe combustion chamber of the cylinder and is further vented at the extreme top end by the uppermost side apertures or ports 9b. It will furtherbe seen that a tight joint is formed between the insulator bushing 5a and the inner peripheral wall of the shell preventing the passage of gas upwardly between the insulator and the shell.

My iiash ignition plug is therefore very quicklyv and thoroughly vented and lled with a new charge of combustive fuel. Due to the shielding of the lower end of the insulator and the electrodes and due to the complete combustion caused by the radial distribution of theV flame, carbon and oil deposits upon the electrodes and lower end of the insulator are substantially eliminated and the life of the plug is greatly prolonged.

In actual use the plug has demonstrated a high efficiency for all the purposes intended.

In the form of the invention illustrated in Figs. 3 and i the structure of the plug is in general similar to the form disclosed in Figs. 1 and 2 with the exceptions, however, that the bottom of the hollow shell extension 9a is imperforate, all of the flame jets being disposed in the sides or peripheral wall and further that the flame discharge apertures as shown are in the form of rectangular slots 20. The explosion chamber E of this second form of plug as in the first form is entirely disposed within the combustion chamber of the engine and is provided with circumferentially arranged discharge apertures at both top and bottom ends, in order that the plug may be quickly and thoroughly Vvented by the suction stroke of the engine. c

From the foregoing description it will be seen that I have provided a simple, inexpensive and highly eincient spark plug of the ash ignition type adapted to eifect a more complete and faster ignition of the combustive gases, having greater durability and preventing the formation of carbon and oil deposits upon the electrodes and lower end of the insulator bushing.

It will, of course, be understood that various changes may be made in the form, details, proportions and arrangement of the parts without departing from the scope of my invention, which, generally stated, consists in a device capable of carrying out the objects above set forth and in the novel parts and combinations of parts disclosed and defined in the appended claim.

What is claimed isz- A spark plug of the flash ignition type comprising a metallic shell having a hollow closed extension and an insulator bushing disposed within said shell, land having a portion tightly fitted within the upper portion of said extension cooperating with said extension to define a spark plug explosion chamber which is disposed entirely within the combustion chamber of the engine, said insulator bushing having a depending reduced end disposed axially of said chamber, electrodes disposed centrally within said chamber, one of .which projects axially Vfrom the reduced end of said insulator bushing, said hollow extension having a series of radially arranged flame discharge apertures in its peripheral wall, some of said apertures being disposed at the extreme, closed, upper end of said chamber and some being disposed at the extreme lower end of said chamber to produce a rapid venting of said chamber after an explosion and to enable flames to be discharged radially from said extension upon explosion within said chamber,

WILLIAM J. STEPHENSON. 

